Depressive Symptoms Are Associated With Objectively Measured Sleep Parameters in Kidney Transplant Recipients.

STUDY OBJECTIVES: Both depression and sleep complaints are very prevalent among kidney transplant (kTx) recipients. However, details of the complex relationship between sleep and depression in this population are not well documented. Thus, we investigated the association between depressive symptoms and sleep macrostructure parameters among prevalent kTx recipients. METHODS: Ninety-five kTx recipients participated in the study (54 males, mean ± standard devation age 51 ± 13 years, body mass index 26 ± 4 kg/m2, estimated glomerular filtration rate 53 ± 19 ml/min/1.73 m2). Symptoms of depression were assessed by the Center for Epidemiologic Studies - Depression Scale (CES-D). After 1-night polysomnography each recording was visually scored and sleep macrostructure was analyzed. RESULTS: The CES-D score was significantly associated with the amount of stage 2 sleep (r = 0.20, P < .05), rapid eye movement (REM) latency (r = 0.21, P < .05) and REM percentage (r = -0.24, P < .05), but not with the amount of slow wave sleep (r = -0.12, P > .05). In multivariable linear regression models the CES-D score was independently associated with the amount of stage 2 sleep (ß: 0.205; confidence interval: 0.001-0.409; P = .05) and REM latency (ß: 0.234; confidence interval: 0.001-0.468; P = .05) after adjustment for potential confounders. CONCLUSIONS: Depressive symptoms among kTx recipients are associated with increased amount of stage 2 sleep and prolonged REM latency. Further studies are needed to confirm our findings and understand potential clinical implications.

[Obstructive sleep apnea in women]. / Az obstruktív alvási apnoe jelentosége nok körében.

The prevalence of sleep disturbances and their symptomatic manifestations may be different in men and women. Women with obstructive sleep apnea are less likely to be diagnosed with sleep apnea compared to men, probably due to atypical symptoms such as morning headaches, symptoms of depression and daytime fatigue. There is a great importance of diagnosis and treatment of sleep disorders regarding quality of life, co-morbidity and mortality in both genders.

Sleep apnea is not associated with worse outcomes in kidney transplant recipients.

Obstructive sleep apnea(OSA) is one of the most common sleep disorders in kidney transplant recipients, however its long-term consequences have only rarely been investigated. Here, we hypothesized that the presence of OSA would be associated with higher risk of mortality and faster decline of graft function in kidney transplant recipients. In a prospective cohort study 100 prevalent kidney transplant recipients who underwent one-night polysomnography at baseline and were followed for a median 75 months. Generalized linear mixed-effects models and Cox regression models were used to assess the association between OSA and the rate of progression of chronic kidney disease(CKD) and mortality. The estimated slopes of estimated glomerular filtration rate(eGFR) in patients with and without OSA were compared using a two-stage model of eGFR change including only OSA as a variable. In this model patients with OSA (eGFR versus time was -0.93 ml/min/1.73 m(2)/yr(95%CI:-1.75 to-0.11) had a similar slope as compared to patients without OSA(eGFR versus time was -1.24 ml/min/1.73 m(2)/yr(95%CI: -1.67 to -0.81). In unadjusted Cox proportional regression analyses OSA was not associated with higher all-cause mortality risk (Hazard Ratio(HR) = 1.20; 95% Confidence Interval(CI): 0.50-2.85). No association was found between the presence of OSA and the rate of progression of CKD or all-cause mortality in prevalent kidney transplant recipients.

Association between lunar phase and sleep characteristics.

OBJECTIVES: Popular belief holds that the lunar cycle affects human physiology, behavior, and health, including sleep. To date, only a few and conflicting analyses have been published about the association between lunar phases and sleep. Our aim was to analyze the relationship between lunar phases and sleep characteristics. METHODS: In this retrospective, cross-sectional analysis, data from 319 patients who had been referred for sleep study were included. Individuals with apnea-hypopnea index ≥ 15/h were excluded. Socio-demographic parameters were recorded. All participants underwent one-night standard polysomnography. Associations between lunar cycle (new moon, full moon and alternate moon) and sleep parameters were examined in unadjusted and adjusted models. RESULTS: Fifty-seven percent of patients were males. Mean age for men was 45 ± 14 years and 51 ± 12 years for women. In total, 224 persons had their sleep study done during alternate moon, 47 during full moon, and 48 during new moon. Full moon was associated with lower sleep efficiency [median (%) (IQR): new moon 82 (18), full moon 74 (19), alternate moon 82 (15); P < 0.001], less deep sleep [median (%) (IQR): new moon 9 (9), full moon 6 (4), alternate moon 11 (9); P < 0.001], and increased REM latency [median (min) (IQR): new moon 98 (74), full moon 137 (152), alternate moon 97 (76); P < 0.001], even after adjustment for several covariables. CONCLUSION: The results are consistent with a recent report and the widely held belief that sleep characteristics may be associated with the full moon.

Obstructive sleep apnea and heart rate variability in male patients with metabolic syndrome: cross-sectional study.

BACKGROUND: Obstructive sleep apnea (OSA) is often accompanied by the metabolic syndrome. Because both conditions are associated with depressed heart rate variability (HRV) separately, our aim was to study whether co-morbid OSA is associated with more reduced HRV in male patients with the metabolic syndrome. METHODS: In this cross-sectional study, 35 men (age, 57±11 years) with the metabolic syndrome (according to International Diabetes Federation criteria) were included. OSA severity was defined by the apnea-hypopnea index (AHI). HRV was assessed by 24-hr ambulatory electrocardiographic monitoring. Standard deviation of all normal-to-normal RR intervals (SDNN), the high frequency power (HFP), and the ratio of low- to high-frequency power (LF/HF) were measured. RESULTS: There were 14, 6, and 8 cases of severe (AHI ≥30/hr), moderate (15/hr≤AHI <30/hr), and mild (5/hr ≤AHI <15/hr) OSA, respectively. Seven patients had no OSA. Patients with mild-moderate or severe OSA had reduced SDNN and HFP values compared to those without OSA. Increasing OSA severity was associated significantly with lower daytime LF/HF ratio [standardized ß regression coefficient (ß)=-0.362, P=0.043] and higher night/day LF/HF ratio (ß=0.377, P=0.023) after controlling for age, duration of diabetes, and severity of metabolic syndrome. CONCLUSIONS: Co-morbid OSA is associated with decreased overall HRV, parasympathetic loss, and impaired diurnal pattern of sympathovagal balance that may further increase the cardiovascular vulnerability of male patients with the metabolic syndrome. The role of the HRV analysis in the risk assessment of these patients warrants further studies.

Lack of association between objectively assessed sleep disorders and inflammatory markers among kidney transplant recipients.

PURPOSE: In patients on dialysis, the results of studies examining the association between sleep disorders and inflammation are controversial. We assessed the association between inflammatory markers and different sleep disorders in a large sample of kidney transplant recipients. METHODS: Cross-sectional study of 100 randomly selected kidney transplant patients who underwent one-night polysomnography ("sleep disorders evaluation in patients after kidney transplantation study") to diagnose obstructive sleep apnea (OSA) and periodic limb movements in sleep (PLMS). Athens Insomnia Scale (AIS) was utilized to assess the prevalence of insomnia. Sociodemographic information and data about medication, comorbidity and laboratory parameters were collected. Levels of inflammatory markers, such as C-reactive protein, serum albumin, white blood cell count, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), were measured. RESULTS: The mean age was 51 ± 13 years, 43% were women, and the prevalence of diabetes was 19%. We found no significant difference in the levels of inflammatory markers between patients with versus without OSA and PLMS. Apnea-hypopnea index showed a significant association with white blood cell count (ρ = 0.23), and weak (ρ < |0.15|), non-significant correlation with the other inflammatory markers. PLM index showed weak (ρ < |0.15|), non-significant correlation with all markers of inflammation. The serum IL-6 level was significantly higher in patients with insomnia (AIS ≥ 10) than in non-insomniacs [median (IQR): 3.2(2.6-5.1) vs. 1.7(1.2-2.9) ng/l; P = 0.009]. The levels of other inflammatory markers were similar between insomniacs and non-insomniacs. CONCLUSIONS: We did not find any association between the presence of objectively assessed sleep disorders and inflammatory markers in kidney transplant patients.

High risk of obstructive sleep apnea is a risk factor of death censored graft loss in kidney transplant recipients: an observational cohort study.

OBJECTIVES: Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular morbidity in the general population. The clinical significance of OSA among kidney transplant patients is unknown. Our aim was to investigate the association of "high risk of OSA" with death-censored graft loss and mortality in a large cohort of kidney transplant recipients. PATIENTS AND METHODS: Using the Berlin questionnaire 1067 prevalent kidney transplant recipients were assessed for risk of OSA. Socio-demographic variables, laboratory parameters and data about graft loss and mortality were obtained from the medical records. Multivariable-adjusted associations of OSA risk with graft loss and with all-cause mortality was assessed in competing-risks regression models. RESULTS: Of the 823 patients who completed the Berlin questionnaire 28% had high risk of OSA (HRO) at baseline. Patients with HRO were older (52±11 vs. 47±13years, p<0.001), had a higher prevalence of diabetes (22 vs. 15%, p=0.018), worse baseline kidney function (estimated glomerular filtration rate: 46±18 vs. 51±19ml/min/1.73m(2), p=0.001) and higher BMI (27±5 vs. 24±4kg/m(2), p<0.001). In multivariate models HRO was an independent predictor of graft loss among females after adjusting for age, comorbidity, hypertension, BMI, kidney function, duration of chronic kidney disease, other laboratory parameters and transplant-related data (HR=3.05; CI: 1.24-7.51; p=0.015), while HRO did not predict graft survival among males. HRO at baseline was not independently associated with all-cause mortality in the sample. CONCLUSION: High risk of OSA is an independent predictor of graft loss among female kidney transplant patients.